cell division

• Cell division is the process by which a parent cell divides into two or more daughter cells, ensuring the continuity of life and the growth and repair of tissues in living organisms.
• All cells are derived from preexisting cellsNew cells are produced for growth, to replace damaged or old cells and for the production of sex cells plants, & animals)

  Differs in prokaryotes (bacteria) and eukaryotes (protists, fungi, plants, and animals)
• The instructions for making cell parts are encoded in the DNA, so each new cell must get a complete set of the DNA molecules
• DNA, or deoxyribonucleic acid, is a molecule that carries the genetic instructions used in the growth, development, functioning, and reproduction of all known living organisms.
• DNA replication is the process by which a cell duplicates its DNA to ensure that each daughter cell receives an identical copy of the genetic material during cell division.
• A chromosome is a thread-like structure composed of DNA (deoxyribonucleic acid) and proteins, and it carries geneticinformation.
• All eukaryotic cells store genetic information in chromosomesMost eukaryotes have between 10 and 50 chromosomes in theirbody cellsHuman body cells have 46 chromosomes or 23 pairs
• A karyotype is a visual representation of the complete setof chromosomes in an organism's cell
• Chromatin is the complex of DNA and proteins that makes up thegenetic material in the nucleus of a eukaryotic cell during theinterphase of the cell cycle.
• • A chromatid is a single DNA strand in a replicated chromosome.• Centromere, structure in a chromosome that holds together thetwo chromatids (the daughter strands of a replicated chromosome).
• A chromosome is a condensed and visible structure formed by the coiling and folding of chromatin.
• Asexual reproduction involves a single cell dividing to make 2 new, identical daughter cells
• Mitosis & binary fission are examples of asexual reproduction
• Sexual reproduction involves two cells (egg & sperm) joining to make a new cell (zygote) that is NOT identical to the original cellsMeiosis is an example
• Prokaryotes such as bacteria divide into 2 identical cells by theprocess of binary fission
• Single chromosome makes a copy of itself in prokaryotes
• Cell wall forms between the chromosomes dividing the cell
• The cell cycle is a series of events that occur in a cell, leading to its division and the production of two daughter cells
• Cyclins are proteins that play a crucial role in regulating the progression of the cell cycle, particularly at key checkpoints. They work in conjunction with cyclin-dependent kinases (CDKs), forming complexes known as cyclin-CDK complexes.
• Stages of the Cell CycleG1 - primary growth phaseS – synthesis; DNA replicatedG2 - secondary growth phaseM - mitosisC - cytokinesis
• Interphase - G1 Stage 1st growth stage after cell division Cells mature by making more cytoplasm & organelles Cell carries on its normal metabolic activities
• The G1 checkpoint is the main decision point for a not to divide cell – that is, the primary point at which it must choose whether or
• At G1 a cell checks the following: cell size, nutrients, growth factors and DNA damage
• Interphase – S StageSynthesis stageDNA is copied or replicated
• Interphase – G2 Stage2nd Growth StageCells continue to growChecks for DNA replication errorsduplicates a microtubuleorganizing structure called the centrosome.
• At G2 checkpoint a cell checks the following: DNA damage and DNAreplication completeness